The present invention relates to cutting tool placement devices for spindle-driven shaping machines. More particularly, the present invention relates to alignment tools and gauges for accurately and repeatably locating a cutting tool plane of motion and for placing the tip of a cutting tool in a desired plane parallel thereto.
In many applications involving spindle-driven shaping machines, such as a lathe, it is often desirable to place the tip of a cutting tool accurately in a cutting plane passing transversely through the axis of rotation of the spindle. This is especially apparent during facing operations where a misplaced shaping machine cutter may leave a raised nub at the center of the workpiece. Numerous tools have been developed for positioning the tip of the cutting tool to the appropriate location on the workpiece.
One legacy tool setting gauge is disclosed in U.S. Pat. No. 2,777,210 to Johnson, et al., which is used to position the cutter of a machine tool on a plane which intersects the axis of rotation of a workpiece. The tool setting gauge of Johnson includes a V-shaped clamping device, a tool positioning surface parallel to a base surface, and a rotatable spirit level vial holder. The tool is aligned to the tool bed, i.e., cutting tool axis of a particular machine by placing the base surface against the tool slide of the machine tool and rotating the spirit level vial holder until the bubble therein is centered. The vial holder is then clamped in place by means of a backing screw. Once the clamp has been tightened, the tool gauge is then affixed to a workpiece via the clamping device and the tip of the cutting tool is adjusted until it just comes flush with the tool positioning surface. The tip of the cutting tool is then located in a cutting plane which includes the axis of rotation of the workpiece.
The tool setting gauge of Johnson suffers several shortcomings rendering its effective use on modern shaping machines limited. First, with only the manual rotation of the spirit level vial holder as means for locating the tool positioning surface in the proper orientation, the tool setting gauge of Johnson is grossly inaccurate and minimizes the accuracy of modem machine tools. Further, the tool setting gauge of Johnson is constructed such that essentially the entire weight of the tool is located on one side of the workpiece, making it difficult to established maintain a desired orientation of the gauge (i.e., bubble in spirit level centered) while simultaneously attempting to locate the tip of the cutting tool flush with the tool positioning surface. A still further shortcoming is that the gauge of Johnson may only be used to position a cutting tool on a plane that includes the axis of rotation of the workpiece, which may not be the optimum cutting plane in certain applications.
The alignment tool of the present invention overcomes the shortcomings of Johnson and similar gauges of the prior art by providing accurate cutting axis locator means, adjustable weight distribution, and cutting plane indication means to indicate a plurality of parallel cutting planes, each located at varying distance from the cutting plane that includes the axis of rotation of the workpiece.
One object of the present invention is to provide an alignment tool for setting the tip of a cutting tool at a desired location on a workpiece in a spindle-driven shaping machine with cutting axis locator means that accurately and repeatably locates a cutting plane of any angle independently from the orientation in space of the shaping machine.
Another object of the present invention is to provide an alignment tool with adjustable weight distribution means for positioning the center of gravity of the alignment tool at a desired location during cutting tool placement procedures.
A still further object of the present invention is to provide an alignment tool with a plurality of cutting plane indicators, each parallel to the longitudinal center line of the alignment tool and located at varying distances from the cutting plane that includes the axis of rotation of the workpiece.
These and other objects of the present invention are realized by an alignment tool which includes an arbor clamp for positioning the longitudinal center line of the alignment tool on the axis of rotation of the spindle of the shaping machine; a displaceable counterweight for positioning a longitudinal center of gravity of the alignment tool; an indicator surface parallel with the longitudinal center line of the alignment tool; a plurality of cutting plane indicators for indicating a point on a corresponding cutting plane; and cutting axis locator means for aligning the longitudinal center line of the alignment tool to the cutting tool axis of the shaping machine.
In one embodiment of the present invention, the cutting plane indicators include a protruding anvil to be placed against the tip of the shaping machine cutter.
In another embodiment of the present invention, each cutting plane indicator is a laser spot emitted from a laser coupled to the alignment tool body.
In another embodiment of the present invention, the cutting axis locator means includes coarse and fine indicator means.
In yet another embodiment of the present invention, the coarse and fine indicator means of the cutting axis locator means are spirit level vials.
In still another embodiment of the present invention, the cutting axis locator means includes coarse and fine adjustment means.
In yet another embodiment of the present invention, the cutting axis locator means is an electronic level.